Portable liquid filtering apparatus



Feb. w, w48. E. A. ROBETSON K 2,436,977

PORTABLE LIQUID FILTERINQAPPARATUS Filed May 13, 1944 2 Sheets-Sheet l I N VEN TOR. 15 M ED. 1N AROBERTSON 23 17 BY n E Q2 18 l Agr m Feb. 17, 1948. E. A, RBERTSN 24365077 PORTABLE LIQUID FILTE'RING APPARATUS Filed. May 15, `3.91m l 2 sheets-sheet 2 JNVENTOR.

E DWI N A ROBERTSON AGENT Patented Feb. i7, 1948 PORT 1.

'it LIQUID TE Edwin Ai. Robertson, Sandus,

by mesme assignments, to 'Elteflein i c arra'rus Ohio, assignor, lino., Newark,

N. J., a corporation of Delaware Application May 13, 19M, Serial No. 535, d31

(Cil. 21B-9d) 1 claim. l

This invention relates to improvements in liquid filtering apparatus. In particular, it deals with portable iiltering devices which may be used to remove suspended particles from contaminated water by screening, straining, clarifying, and iilteringas the requirements dictate, so that the contaminated or unfiltered water can be converted to water which is fit for human consumption and use.

Many eiiicient methods been devised and ltering media comprise a great variety of substances. Mechanical equipment used in filtering consists mainly of pumping devices to circulate liquid, various tanks and piping for supply and conveyance of ltered and unfiltered liquid, and the filtering unit. If a lteraid is employed it becomes necessary to supplement the basic filtering equipment described above with such devices, conveyances, and apparatus as may be required for storing, back-flushof filtering liquids have lng, or for other functions which are added to the process.

When removing relatively large solids from liquids it is practical to use merely a mesh screen corresponding to the size of the particles to be removed. As the size of the particles in suspension decreases, filtering is accomplished with such porous materials as stone or cloth. In order to remove particles which are extremely small and which pass through the usual porous materials it becomes necessary to employ granular or powdered filter material or filter-aid such as asbestos, diatomaceous earth, activated carbon, and like substances which may also include properties of adsorption, bleaching, or polishing to the mechanical screening properties.

In commercial filtering procedures, fairly large quantities of liquid are considered. Equipment for such filtering applications is, therefore, extensive and bulky. Automatic controls are involved in conjunction with the equipment and prime movers of some description are necessary for driving pumps or accessories to the filtering apparatus. It is an object of this invention to provide a iiltering apparatus which is portable and manually operable, and which can be readily adapted to filter liquids efficiently in relatively small quantities. A further object of this invention is to provide a portable ltering unit which can be adapted to filtering out solids of various sizes and descriptions from liquids and particularly for filtering water for human use and consumption. Still further objects of myinvention are to provide a filter of simple and durable construction with all parts contained as a unitary structure having a replaceable `cartridge-type filter medium and which may be used by soldiers, campers, explorers, or other individuals who require filtered water in locations which are remote from a supply of potable water.

With these and other objects in view which will be apparent throughout the description, the invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly dened by the appended claim, it being understood that such changes in the precise embodiment of the invention may be made as come within the scope of the claim.

The accompanying drawings illustrate examples of physical embodiments of the invention constructed according to the best modes so far devised for the practical application of the principles thereof and in which:

Figure 1 is a longitudinal view principally in section showing a typical style of filter unit employing my invention;

Figure 2 is an end elevation view taken from below the filter unit;

Figure 3 is a transverse section taken on the line 3-3, Figure 1;

Figure 4 is a fragmentary section view taken on the line -B, Figure l;

Figure 5 is an elevation view partially in section showing a replaceable filtering medium used with my invention;

Figure 6 is a, longitudinal view in section showing a modied design of the filter portion of the unit; and

Figure 'l is a view partly sectioned showing a modified design of a .replaceable filtering medium.

Referring to the drawings in which like numerals are used to identify like parts throughout the several views, numeral l0, Figure 1, generally indicates a hand pump employed to draw unfiltered liquid through a, iter portion I2 and to discharge filtered liquid from a hose assembly generally indicated at 43.

The pump Il) comprises a tubular metal barrel I8 having a smooth inner surface which terminates at its upper extremity in an open end with external threads to which a discharge cap is attached, and at its lower extremity in an enlarged portion with a hexagonal exterior and internal threads for attaching a filter housing. Slideably disposed within the'pump barrel I8 is a pump piston 2E constructed of metal or other suitable material which is threadedly fastened to a piston rod 2l. A pump handle 28 is fastened on the end of the piston rod 21 opposite to the piston end and is provided in order to permit manual operation of the assembly as will be later described.

The tliter retainer housing I6 is assembled to the lower portion of the pump barrel I8 at the female thread heretofore described. This housing is of generally cylindrical consuration comprising a relatively thin-walled metal portion to which is assembled the-hollow outlet 20 which permits passage of liquid to the pump from the iilter portion. The outlet 20 may be joined to the housing i6 as by spinning over its end opposite the male threaded portion, thereby retaining a projecting circumferential shoulder against the housing. The joint may be additionally strengthened by soldering or brazing. also gasketed if it is desirable in making it leak-proof.

The lower end of the housing I6 is provided with male exterior threads II for attaching the disk shaped housing cap i4. It will be noted that this assembly of the cap I4 to the housing i6 serves to retain a replaceable filter cartridge i3 in iixed location within the housing. A projecting flange 23 circumferentially disposed on the replaceable filter cartridge I3 serves as a support in the assembly of the housing I 6 and cap i4, wherein this flange 23 is held in place between the face 2l on the housing and the ledge 22 on the cap. The iiange 23 also serves to prevent positioning of the replaceable cartridge I3 in the filter unit in a reverse direction to that which is intended in the cartridge design. If it is desirable, a ring gasket i1 may .be `placed as shown in Figure l between the flange 23 and the face 2| in order to insure a leak-proof joint between the housing I6 and cap i4 and for preventing seepage of contaminated water irough this joint.

Referring now to Figure 5, the filter cartridge i3 comprises a thin metal shell 24 fabricated of readily deformable material. Rolled-in` edges on material 25'. A rubber or plastic cap 24' may be moulded over the open ends of cup lters il' to seal thev powdered material between the cups. This modification as shown in Figure 6 assembled with component parts provides a greater filter area per unit of filter diameter than the modication of Figure 5. Housing I6' is provided with female threads for assembly with an outlet fitting 2li' on the pump barrel I8'. Replaceable filter cartridge i3' is retained in position at assembly by locking the ledge 23' between the surface 22' on the fitting 20 and the ledge 2i' on housing I6'. Gasket i1' would be employed to seal the joint at ,this location.

As will be noted in Figure 1. a circular opening 48 is provided at the lower extremity of the filter portion of the unit. A coarse screen 49 is rigidly fastened in place within this opening to prevent the passage of coarse solids into the pump. A ap valve disk 39 with a centrally disposed opening is interposed at the junction of outlet 20 and pump barrel i8. Flexible closure member 31 is fastened to the valve disk 39 by pin 38 to permit passage of liquid in an upward the top and bottom serve to retain two rigid disk lters il in place, between which is a contiguous layer of powdered or granular filtering material 25 such as asbestos, diatomaceous earth, or activated carbon. If it is desirable, this material 25 may be constituted of a mixture of substances for a particular application, or it may comprise layers of different materials. The rigid disk-like nlters Ii may be constructed of stone as carborundum or of other material having desired porosity and filtering properties. Material specifications for the replaceable cartridge are chosen to perform a desired ltering function of clarification or cold sterilization depending upon the conditions of the unfiltered liquid.

When assembling the filtering cartridge I3 the retaining shell 24 may have one of its inturned ends formed prior to the assembly operation and Y a single disk li set -in position on the ledge provided thereby. Subsequently. the powder-like material 25 may be inserted in a measured quantity in this sub-assembly and over this would be placed the second lter disk Il. The final operation in the assembly of this cartridge would be turning-in the opposite end to complete the cartridge in a manner which would hold the second disc in place and prevent the loose material from falling out.

In an alternative construction as shown in Figure 7 the replaceable filter cartridge I 3' may be made of two rigid cup-shaped lters il of dissimilar sizes situated one within theother between which is the powdered or granular ltering vdirection only when the pump is held upright.

In the modication shown in Figure 6 this ap valve, comprising the disk element 39', and the attached flexible closure element 31' are retained in position in a 4counterbore in outlet 20' by means of a suitable open spring ring 55 which may be snapped in a recess in the counterbore provided.

-Likewise the piston 26 is provided with a longitudinally disposed opening 36 which is sealed by flexible nap valve 34 pinned to the piston at 35 permitting liquid to pass upwardly only with respect to the pump. The flexible piston packings 33 directed upwardly and downwardlyfrom the central circumferential portion of the piston serve as a seal in both directions in the operation of the piston within the pump barrel.

Pump discharge cap 3i is fastened to the top 'threaded portion of the pump barrel I8. .An ap'- erture in the top of cap 3l provides for sliding passage and guiding of the piston rod 21 and a packing 30 is disposed in a cup-shaped portion at the top of cap 3i above this aperture. This packing material is held in place by the threaded bushing 29 and serves to seal this opening against' leakage during reciprocation of the piston 26 without undue binding. At the side of the cap 3l are the radially disposed ports 32, more clearly shown in Figure 4, which permit passage of liquids from the pump barrel. The specially constructed inside tapered hose connection 41 is rotatably fitted against the correspondingly outside tapered projection on cap 3l and over ports 32 in order to guide liquid from the pump to the hose 4| attached to hose connection 41, and thence to the nozzle 40. A seal is provided at the rotatable fitting 41 by outside tapered plug 46 which is restrained against the inside taper in thefitting 41 by pressure of the spring 45 disposed between plug 46 and screw 44 threadedly fastened to the circular portion of the ribbed section of cap 3l between ports 32.

Unrestricted swinging of the hose assembly 43 is possible when hose 4i is detached from clip 50 to direct the filtered liquid in any direction or to the event that it is desirable to carry the filter unit over an arm or shoulder.

In operation the filter unit may be dropped into a suitable source of water supply so that the screened opening 48 is immersed. The piston is then reciprocated, the operator holding the pump barrel i8 in one hand and the pump handle 28 in the other hand. Considering now the flow of liquid, the upward travel of piston 28 will create vacuum in the filter portion tending to draw in liquid from the water supply. Primary screening will take place as the liquid passes through opening 48, Thereafter, the lower filtering disk or cup Il will serve to restrain a large quantity of suspended material.

Further filtering and clarification is effected as the liquid continues upwardly in the direction of the arrows through the powdered or granular material 25 and thence through the upper filter disk or cup Il. When the liquid reaches the lower portion of the pump barrel above the filter cartridge the process of filtration or cold sterilization is completed. Thereafter, passage through the pump is merely a matter of direction and ow as the result of pressure exerted by the pump mechanism, Since one-way valves are provided in the lower portion of the pump barrel and in the piston, a complete cycle will be: first, 'on the upward stroke of the piston, the withdrawal of liquid during which operation air is displaced s0 from above the piston; and, second, on the downward stroke, liquid remains in the pump barrel by forced closure of the nap valve in the lower portion of the pump barrel, and the piston is permitted passage downwardly through thisv liquid by forced opening of the flap valve in the piston. Each of the following upward strokes will withdraw liquid below the pistons and discharge liquid above the piston.

' Flow of filtered liquid will be carried on until the screen or filter cartridge becomes completely clogged with suspended material. At this time discharge will no longer take place and it will be necessary to provide a replacement filter cartridge. The quality oi' liquid being filtered will determine the quantity permitted to flow through the illter unit before such replacement becomes necessary.

It is to be understood that the form of my invention, herewithshown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size, and arrangement of parts may be resorted to, without departing from the spirit of my invention.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

In a portable filtering apparatus, in combina- 6 tion, a filter housing having an outlet opening, a filter housing cap threadedly joined to said filter housing and provided with an intake opening, a replaceable nlter cartridge within said filter housing, said cartridge having an impervious open-ended shell within the ends of which are situated a pair of rigid pervious filter discs separated by a layer of loose filtering material, said cartridge being secured in place within said housing by the joinder of said housing and said cap, a sealing gasket between the filter housing and the exterior of the filter cartridge whereby all uid passing through the lter housing must pass within the filter cartridge. a manually operable liquid pump in threaded engagement with the filter housing and having an intake communicating with the housing outlet, a discharge port on the liquid pump, and a discharge conduit in communication with said discharge port, said discharge conduit including a fitting swivelably fastened to the liquid pump at the discharge port whereby the discharge conduit may be moved with respect to the discharge port during filtering.

EDWIN A. ROBmTSON.

REFERENCES CHTED The following references are of record in the file of this patent:

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